Aircraft towing vehicle having steered nose wheel lifting mechanism

Abstract

An aircraft towing vehicle is equipped with an aircraft nose wheel lifting and securing mechanism. The nose wheel is received in a U-shaped recess of the vehicle chassis, the lifting mechanism being constructed to grip the wheel from behind and underneath and to then push it up a ramp. The tilt angle of the lifting mechanism as it advances towards the wheel is controlled by a steering linkage such that the lower, freely movable segment of the lifting mechanism is tilted farther forward and beneath the nose wheel at the beginning of the nose wheel engaging operation, while conversely, a rigid upper segment is tilted farther forward as the engaging operation continues to completion.

We claim: 
     
       1. An aircraft towing vehicle comprising a vehicle frame constructed to be maneuvered about a surface in forward and aft directions, the frame including a generally U-shaped, rearwardly open recess formed to receive an aircraft nose wheel therein; a ramp carried by the frame and positioned at a forward end of the recess for receiving and supporting the nose wheel;   a lifter having a lower segment and an upper segment for engaging an aft portion of the nose wheel and moving the nose wheel onto the ramp;   lifter support means pivotably mounted to the vehicle frame for moving the lifter in a generally forward direction towards the aft portion of the nose wheel;   means connecting the lifter to the lifter support means and permitting pivotal movements of the lifter relative to the lifter support means about a generally horizontal axis;   power drive means operatively coupled with the lifter for moving the lifter relative to the frame and applying a forwardly directed force to the aft portion of the nose wheel and thereby move the nose wheel in a forward direction onto the ramp;   control means operatively coupled with the lifer and causing pivotal movements of the lifter relative to the lifter support means about the horizontal axis when the power drive means moves the lifter so that during an initial phase of such movement the lower segment travels relatively farther in the forward direction and during a final phase of such movement the upper segment travels relatively farther in the forward direction; and   whereby, during the initial movement phase, the lower lifter segment engages the nose wheel and facilitates the movement of the nose wheel onto the ramp and during and after the final phase of the movement the upper lifter segment firmly secures the nose wheel to the ramp and thereby to the towing vehicle.   
     
     
       2. An aircraft towing vehicle according to claim 1 wherein the lifter support means is pivotable relative to the vehicle frame about a substantially upright axis. 
     
     
       3. An aircraft towing vehicle according to claim 1 wherein the upper lifter segment is fixed and rotationally immovable relative to the control means, and including means mounting the lower lifter segments for relative pivotal movements about a second horizontal axis. 
     
     
       4. A towing vehicle according to claim 3 wherein the second horizontal axis is relatively lower than the first mentioned horizontal axis. 
     
     
       5. A towing vehicle according to claim 1 wherein the upper and lower lifter segments are each defined by a set of multiple, parallel rollers. 
     
     
       6. A towing vehicle according to claim 1 and constructed to tow aircraft of predetermined types, and wherein the lifter has a vertical extent when in its operating position which is less than the diameter of the smallest aircraft nose wheel of the predetermined aircraft types and greater than one-half the diameter of the largest nose wheel of the predetermined aircraft types. 
     
     
       7. A towing vehicle according to claim 1 wherein a side of the lifter facing the nose has a generally concave configuration. 
     
     
       8. A towing vehicle according to claim 1 wherein the power drive means pivotably moves the lifter and the lifter support means in a forward direction towards and against the aft portion of the nose wheel. 
     
     
       9. An aircraft towing vehicle according to claim 1 wherein the means connecting the lifter includes a shaft, and wherein the control means comprises a control linkage mechanism including a plurality of pivotally interconnected links and a control arm, means pivotably connecting the control arm to the shaft for relative pivotal movements between the control arm and the shaft about a generally upright axis, the control linkage being further pivotally coupled to the vehicle frame and dimensioned so that the shaft pivotally moves relative to the lifter support to effect relative faster forward movements of the lower lifter segment and the upper lifter segment during the initial and final phases of the lifter forward movement, respectively.